Matrix blank



Patented Aug. 13,1940

Claude E. Hensley, Oklahoma City, Okla.

Application July s. 1938, Serial No. 217,521

3 Claims.

This invention pertains to matrices and more particularly to flongs or mats used in the preparationof matrices. A flong is a backing" sheet used in forming a matrix, and the later molding of a stereotyping plate. The type of flong in present use is simply a )paper mat made of sub-' stantially homogeneous'moisture absorptive mate- 'rial, and it is prepared with one comparatively smooth surface for receiving the impression, and

one rougher surface. The unimpressed sheets are usually kept in a humidor, the air in which is kept relatively humid. The sheets absorb a considerable amount of moisture from the air in the humidor and they are shaped while in this relatively damp condition. Technically these flongs are known as dry mats but the are shaped while in a relatively moist condition in order to eliminate the breaking of the surface of the mat, as well as to reduce the amount 30 of pressure necessary to secure a clear out impression of the various kinds of type which are pressed against the sheet.

After the impression has been made the sheets.

are placed in a drying ovenin an attempt to 25 entirely remove the moisture from them. Due to ture still remaining in the sheet, forms vapor which forces itsway into the molten metal, and 35 causes what is known in the trade as pin holes. These pin holes, render the printing plate thus formed imperfect and it is sometimes necessary to make as many as live or six casts from a single i a matrix before all'the moisture in the matrix has 40 been driven out so that a clear plate can be obtained on the next casting.

My. invention has three chief objects. First,

/ to reduce the actual moisture content necessary 'to maintain the flong in a suiiiciently pliable form; second, to make it easier to remove the' moisture from the sheet after it has been im-{ pressed; and third, to positively prevent. the

small amountof moisture remainingin the sheet after-the drying process from forming vapor 'and 50 causing 'pin holes inthe molten type metal when it is poured against the matrix.

The details in the construction of a preferred form of my invention, together with other objects attending its production will be better .un-

55 der'stood from the following description when during the drying process.

it is, therefore, almost impossible to secure an read in connection with the accompanying drawing which is chosen for illustrative purposes only, and in which.

Figure 1 is a perspective view of a flong formed according to my invention; 5

Figure 2 is a fragmentary sectional view of the flong shown in Figure 1; and,

Figure 3 is a transverse fragmentary section showing the. relative positions of the casting box, flong, and the molten metal during the 10 casting of the printing plate.

To accomplish the objects enumerated'above I prefer to form the fiong or backing sheet of from 80% to 90% paper pulp and 10% to finely powdered aluminum, copper or other com- 15 paratively soft exceptionally good heat conducting metals. The pulp and the powdered metal are thoroughly mixed before the mixture is rolled w into sheets. A sheet formed from sucha mixture contains a smaller quantity of absorbent material 20 than sheets of the same size which are being used at present. Therefore, a sheet of the same size actually contains a smaller quantity of moisture after it has been treated in the humidor than a sheet made of 100% paper pulp. The metal particles in the sheet are highly conductive of v heat and, therefore, when the composition sheet isplace'd in the drying oven, a much greater percentage of the moisture is actually removed than would be removed from the sheet made of pure paper pulp.- v i I In addition, during the impressing or shaping of the sheet, the metal particles actually aid in maintaining the sheet in its impressed form. These particles are inherently very sensitive to pressure and thus also aid in making a very clear and e'xactimpression in the surface of the sheet. Sheets made of 100% paper pulp shrink both in length and in width during the impressing of the type on the surface of the sheet, as wellas An advertisement which isto be 10" x 10" when the newspaper is actually printed, vmust be .set up to cover approximately 10 x 10 when the imprint is formed in the sheet. The shrinkage varies and exact desired size in the finished plate. Under test I have proven that the shrinkage of the metal content sheet is approximately "to less than the shrinkage of the paper pulp sheet. I have also established the fact that the. shrinkage is much more uniform than inthe pure paper pulp sheets.

In .addition to eliminating .a deal of the moisture content trouble by making a metal content 55 sheet, my invention contemplates the surfacing of the imprint receiving side of the sheet with a thin layer of aluminum foil. Although other metals having a high melting point may be used, I prefer to use aluminum because it is impervious to water vapor, it forms a clear impression in the surface of the sheet, it aids greatly in standardizing the shrinkage, and what is more important, its melting point is sufiiciently high that it is unaffected by the temperature of the molten metal which is poured on the sheet to form the printing plate. The foil may be attached to one surface of the sheet by means of any suitable paste. I prefer to use a paste similar to that described in Patent No. 978,824 issued December 13, 1910 to M. A. Droitcour.

It will readily be seen that if even a 100% pure paper pulp sheet is provided with a surface .of aluminum foil, the moisture in the sheet which remains after the sheet has been removed from the baking oven would be-positively prevented fromforming vapor and passing into or against the surface of the molten metal. The vapor formed would first create a' pressure between the inner surface of the aluminum sheet and the adjacent surface of the casting box, which pressure would aid in forcing the aluminum sheet snugly into every single depression and crevice around the type which is being formed in the molten metal. The vapor is prevented from actually coming in contact with the molten metal and the plateformed from such a sheet would, therefore, be unaffected and, the pin holes in the plate would be completely eliminated. It is contemplated thatthe exposed surface of the aluminum foil will be highly polished so that a plate formed from a matrix constructed according to my invention would have much smoother type face than plates formed from 100% paper pulp matrices.

' From the above. explanation it will be seen that I have produced a flo r matrix sheet which will remain in a tly pliable and moldable condition with less moisture content than is necessary with flongs presently in use; that the moisture remaining in the flong can be more easily removed due to the fact that the metal particles conduct the heat and distribute it more evenly throughout the body of the material of which the flong is made; and that I have provided a flong, dry mat, or matrix blank which completely eliminates pin holes in the printing plates due to water vapor.

In the figures, numeral 5 represents the backing sheet and'numeral 6 represents a sheet of metalfoil. Numeral! indicates the casting box and numeral 8 represents the molten metal which ispoured against the matrix to form the plate. With respect to the scope of my invention I do not wish to be limited except by the prior art and by the appended claims.

I claim: v

1. A flong or matrix blank comprising a thin backing sheet, composed of'a mixture of from 80% to 90% paper pulp and from 10% to powdered aluminum; and a thin facing sheet of aluminum cemented on said backing sheet for receiving the impression.

2. A flong or matrix blank comprising a backing sheet composed of a mixture of from 80% to 90% paper pulp and from 10% to 20% powdered copper; and a thin facing sheet of copper cemented on said backing sheet for receiving the impression.

3. A fiong or matrix blank comprising a backing sheet composed of from 80% to 90% paper pulp and from 10% to 20% finely powdered metal having a definite melting point above 700 F. and having a coefficient of thermal conductivity of at least .50 measured in calories per second per centimeter per degree centigrade; and a thin facing sheet of the. same metal cemented on said backing sheet for receiving the impression.

CLAUDE E. HENSI.IEY. 

